It has been established in the scientific literature that the elevation of growth hormone levels in mammals upon administration of GH-releasing compounds can lead to enhanced body weight and to enhanced milk production if sufficiently elevated GH levels occur upon administration (c.f., P. K. Baker, et al., J. Animal Science 59 (supplement 1), 220 (1984): W. J. Croom et al., J. Dairy Sci. 67 (supplement 1), 109 (1984): S. N. McCutcheon et al., J. Dairy Sci, 67, 2881 (1984)). Further, it is known that the elevation of growth hormone levels in mammals can be accomplished by application of known growth hormone releasing agents, such as the naturally occurring growth hormone releasing hormones disclosed by P. Brazeau et al., Proc. Natl. Acad. Sci. 79, 7909 (1982), and M. O. Thorner et al., Lancet 1,24 (1983)).
The elevation of growth hormone levels in mammals can also be accomplished by application of growth hormone releasing peptides (GRP's), some of which have been previously described (C.f. C. Y. Bowers et al., Endocribology 114, 1537 (1984), F. A. Momany et. al., Endocrinology 114, 1531 (1984) and C. Y. Bowers, 7th International Congress of Endocrinology Abstracts, 464 (1984)).
Antibodies to the endogenous growth hormone release inhibitor, somatostatin (SRIF) are also used to elevate GH levels. In the last case, growth hormone levels are elevated by removing the endogenous GH-release inhibitor (SRIF) before it reaches the pituitary, where it inhibits the release of GH (c.f. W. B. Wehrenberg et al., Endocribology 115, 1218 (1984)).
Finally, it has been shown that some compounds such as morphine (c.f. C. Rivier et al., Endocrinology 100, 238 (1977)) and other alkaloids (c.f. C. Y. Bowers, Endocrinology 117, 1441 (1985)) and DAla.sup.2, DLeu.sup.5 -enkephalinamide (c.f. E. L. Lien et al., FEBS Letters 88, 208 (1978)) also release growth hormone by acting on the hypothalamus.